1. Field of the Invention
A method and apparatus for treating a reserve pit and its contents to enable the pit to be earth filled more quickly and economically following a drilling operation.
2. Brief Description of the Prior Art
In the drilling of oil and gas wells, it is common practice to provide an earthen pit adjacent the drilling site to accommodate substantially all of the undesirable waste by-products of the drilling process. Such materials placed in the reserve pit include spent drilling mud from the shale shaker, bit cuttings from the well bore as contained in the spent drilling mud, both salt and fresh water, depending on the particular type of drilling being done and the location of the drilling, and various residual hydrocarbons and drilling mud additives.
With the heightened awakening of the national conscience toward environmental pollution and conservation of natural resources, state regulatory agencies have enacted regulations which more stringently than previously control the disposition of contaminants or waste materials generated in various industries, and the industry of oil and gas well drilling has been included in the concerns of such agencies. In the latter regard, it has become common practice to require, by such regulations, the refilling of reserve pits after the drilling of an oil or gas well has been completed. Since the reserve pit will frequently contain large quantities of sundry liquids and slurries developed in the course of the drilling operation, before the pit can be filled with earth these liquids must in some way be removed from the pit.
A practice which has been widely followed is to remove the liquids from the pit into tank trucks, and then transport the liquids to an approved disposal site, such as a disposal well drilled into an impermeable rock or underground cavity in such rock, so that the liquids thus do not freely migrate to ground water supplies and aquifers. The regulations relative to policing and filling of reserve pits generally impose a time limitation on the well operator and/or drilling contractor by which the reserve pit must be filled with earth. Since the liquid content of most pits will seldom evaporate within this time, and since drainage to surrounding lands or water sheds is generally neither feasible nor legal, the method of truck transport to adequate and approved disposal sites has been the most frequent method employed for removing the water content of the reserve pits to facilitate subsequent filling of the pit with earth in compliance with regulations.
It has unfortunately been a practice in preparing to satisfy the requirements for earth filling reserve pits for many truck operators to bootleg the waste liquids in the sense of making nocturnal dispositions of these wastes into streams, and at landfill locations not approved for such dumping, and constituting ecological hazards by reason thereof. Policing of disposition is difficult and the disinclination of well operators to adequately surveil the waste disposition activities of truckers is in part motivated by the expense attendant to legitimate and authorized disposition of such liquid wastes.